The present invention generally relates to the removal of residual materials from containers for disposal or recycling. More specifically, the present invention relates to a method and apparatus for cleaning residues from the surface of containers by the use of low temperatures. In addition, the present invention relates to a container with features that facilitate cleaning by the use of low temperatures.
The disposal of wastes has become a great concern due to the environmental problems associated with hazardous materials. Of even more immediate concern are the economic problems associated with rising costs and reduced capacity of landfills, as well as the tighter governmental regulations concerning waste generators, air pollution, employee safety and fire prevention. Consequently, disposal of containers and the residual materials remaining therein can be a costly and time consuming endeavor. Emphasis has been placed on cleaning the residues from the containers so that only the residues, and not the containers, are subject to costly hazardous waste disposal. This leaves the containers available to be reused, recycled, or disposed of in a less expensive non-hazardous waste landfill.
One benefit of using an intermediate bulk container (IBC) is the ability to reuse the containers. IBCs range in size from 85 gallons to 550 gallons and come in a variety of shapes and are fabricated using a variety of materials, such as plastic, aluminum, steel and stainless steel. In order to reuse an IBC, the container must first be cleaned. Often the product being shipped in the IBC is viscous, sticky and/or hazardous. Sometimes the residue sets up after exposure to moisture or water, or expands in volume as the result of the cleaning agent. Further, cleaning these containers has been made more difficult as a result of new and ever changing EPA, OSHA and local fire regulations and zoning laws.
The U.S. government has established guidelines under the Resource Conservation and Recovery Act (RCRA) that specify the cleanliness requirements for disposal of containers as non-hazardous waste. Nevertheless, some states are imposing bans on the disposal of even clean containers in landfills as a remedy for rapidly diminishing landfill capacity. This leaves reuse or recycling of the containers as the only alternative.
A broad range of residues of expended commodities are subject to costly hazardous waste disposal. Some of these residues include, but are not limited to tars, lubricants, mastics, inks, coatings, solvents, adhesives, sealants, paints, etc. A range of traditional cleaning methods exists to remove such residues from commodity containers. These methods include applying water, steam, soaps, detergents, chemical solvents, abrasives and scrubbing equipment. All of these methods result in an increased volume of waste being created that may be more difficult to dispose of than the original residue. These methods may be costly due to the need of expensive materials, equipment and intensive labor. Even if the residue is not considered hazardous, there may be restrictions imposed by municipal sewage districts that require expensive pre-treatment before the residue and wash liquid may be discharged into the sewage drains.
Typically solvents, caustics and various soaps or detergents have been used to clean various containers including IBCs. What kind of cleaning agent is use is dependent on the type of residue being removed from the container. No matter what cleaning agent is used, the amount of the waste stream is always increased and the removed residue is commingled with the cleaning agent. This approach results in, but is not limited to, an increase in disposal costs, a residue that cannot easily and economically be recycled, potential health hazards for employees, emissions of volatile organic compounds (V.O.C.s) into the atmosphere, and potential environmental liability. Further, some cleaning techniques such as sand, bead or soda blast cause damage to the metal by pitting and thinning of the IBC walls.
As an example of traditional cleaning methods, chemical solvent based cleaning involves numerous disadvantages. The solvents are expensive. They require special care and handling because of their combustibility, corrosiveness and/or volatility. Special ventilation equipment may be required to recover the volatile organic compounds which vaporize during use. Additional equipment may be needed to separate the solvent from the residue waste wash for recycling of the solvent. If not separated, the volume of the waste product is greatly increased. Employees require additional training to safely handle the equipment and materials. Special inspections, building codes and zoning requirements may be difficult to comply with, or require that special facilities be constructed for the cleaning equipment. In the end, most small organizations do not have the resources to properly handle the problems associated with disposing or recycling residue laden containers using traditional methods.
There exists a sizable gap between existing traditional cleaning methods to remove residue from containers and the requirements of industry to clean containers with a cost effective, environmentally safe process. Therefore, there exists the need for a method and apparatus for cleaning residues from containers that does not have the inefficiencies, hazards and environmental liabilities associated with traditional cleaning methods.
In particular, large commodity containers are heavy and difficult to maneuver because of their size. Many have very small openings which makes removal of residue difficult. Therefore, there is a need for new containers that facilitate residue removal low temperature methods of cleaning. Likewise, there is a need for new apparatus to complement these new containers and allow the use of new methods of low temperature cleaning.